<nz-layout>
  <nz-header class="header">header</nz-header>
  <nz-layout>
    <nz-sider [nzCollapsible]=true>

      <ul nz-menu>
        <li nz-menu-item>aaaa</li>
        <li nz-menu-item>aaaa</li>
        <li nz-menu-item>aaaa</li>
        <li nz-menu-item>aaaa</li>
        <li nz-menu-item>aaaa</li>
        <li nz-menu-item>aaaa</li>
      </ul>

    </nz-sider>
    <nz-content>this is content</nz-content>
  </nz-layout>

</nz-layout>
